Article on study conducted on wild birds near geographical locations that have a lot of noise -like the oil and gas operations- found that it stresses them so much that they lay less eggs and the babies are smaller and their growth stunted. There have been several studies about 'unnatural stress' and its severe consequences in birds' health...

Our big male Bodines Amazon can really crank it up, too. We have a very unhappy B=G Macaw. He lived with the same woman for 35 years and she recently died. He screams and screams. I still feel like he is screaming for her. He's quite beautiful, but it's so hard to know what to do for him.

I would assume it has as much to do with the fact that it's an 'unnatural' noise than the actual volume. That's the thing about stressors... people say "Well, it has to be stressful for them to live in the wild, always afraid of predators so it's less stress to live in captivity" but this is actually the opposite of what happens because what they don't take into consideration is that, when it comes to undomesticated [and even domesticated] animals, nature gave them ways of dealing with the 'normal' stressors but not with the ones that are not 'natural' to their environment.

Navre wrote:Our big male Bodines Amazon can really crank it up, too. We have a very unhappy B=G Macaw. He lived with the same woman for 35 years and she recently died. He screams and screams. I still feel like he is screaming for her. He's quite beautiful, but it's so hard to know what to do for him.

He might have been a screamer from before, John. Anybody who kept a parrot starting 35 years ago was, most likely, keeping it at a human light schedule and not too good a diet so I bet he is overly hormonal and has other health issues, too...

Many avian species have long been exposed to loud natural sounds such as streams, waterfalls, and wind. However, anthropogenic noise pollution is a relatively recent phenomenon that birds now have to cope with throughout much of the world. Early investigations on bird responses to noise tended to focus on physical damage to ears, stress responses, flight or flushing responses, changes in foraging, and other behavioral reactions. These studies were often conducted under laboratory conditions because determining effects of noise on freeranging birds is particularly difficult, in that we rarely have the opportunity to isolate noise as a single testable variable. By coupling introduced noise on the landscape (e.g., from gas well compressors) with ecologically similar controls, investigators have recently found additional responses, including avoidance of noisy areas, changes in reproductive success, and changes in vocal communication. Numerous investigators have compared urban birds with their rural counterparts in quieter surroundings and found that at least some birds can compensate for the masking effect of noise through shifts in vocal amplitude, song and call frequency, and song component redundancies, as well as temporal shifts to avoid noisy rush-hour traffic. Sounds have presumably always been part of the environment, but noise pollution has escalated over the past century, especially the past few decades, disturbing the integrity of natural ecosystems. This review provides general background information, updates on the most current literature, and suggestions for future research that will enhance our comprehensive knowledge and ability to mitigate negative effects of noise.